Home Security Sophisticated Mac malware 'aimed at select targets'

Sophisticated Mac malware 'aimed at select targets'

A malicious payload that can attack machines running either the older OS X or the newer macOS appears to be aimed at select targets and only for the purpose of cyber espionage, a senior security researcher says.

Bogdan Botezatu, senior e-threat analyst at Bitdefender's labs in Romania, told iTWire that the new sample appeared to be the Mac version of XAgent, a modular payload that was said to be from a group known as APT28 or Sofacy. This group is said to have Russian links, but no definite proof exists to substantiate this.

Versions of XAgent than can work on Windows, Linux, iOS and Android were found some time back. XAgent for the Mac was just not a rewrite of the iOS version, but rather one with plenty of additional features.

While the Mac version shared some of the features of those for other operating systems, Botezatu said the it had more spying capabilities and could steal iOS backups from Apple computers which contained messages, contacts, voicemail, call history, notes, calendar and Safari data.

On 26 September last year, Palo Alto Networks had identified the Komplex trojan. It had three parts: a dropper, a payload and a decoy PDF file, he said.

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Bogdan Botezatu: "It is very tough and very dangerous getting into the business of identification. And, at the country-level, accusations can have big diplomatic implications."

The Komplex binder was the main executable and served to save the dropper on the system and open the PDF file. The Komplex payload was the final component and it downloaded and executed a file as programmed to do by its command and control servers.

Botezatu said Komplex could be distributed by email, disguised as a PDF document and gain a foothold on a system. Once a host was infected, it would download and run the XAgent malware.

Once started, the main module of XAgent, called BootXloader, would wait for Internet connectivity by pinging, one of Google's DNS servers. Then followed the initialisation of the module for communication with the C&C servers.

After this, Botezatu said MainHandler, the main module for handling C&C commands and spying modules, was started. It would start two communications channels, one for receiving commands and the other for sending data.

There were additional modules in XAgent: CameraShot (not yet implemented), Password (used to obtain passwords from Firefox profiles), FileSystem (for finding, deleting, creating and executing files), FTPManager, InjectApp (to leverage high-level inter-process mechanisms), InfoOS (gathering information from the target like process, list, operating system version etc), KeyLogger, Launcher, RemoteShell, Coder and Cryptor.

Asked if there was definitive proof of XAgent's Russian ancestry, Botezatu said attribution was very difficult. "Everything can be spoofed," he explained. "It is very tough and very dangerous getting into the business of identification. And, at the country-level, accusations can have big diplomatic implications."

But, he said, looking at the files, they appeared to have been compiled at hours matching daylight hours in Moscow.

Botezatu said the code was not of the same grade as that in Stuxnet, which was used to target nuclear plants in Iran, and claimed to be written by US and Israeli state programmers.

"Stuxnet had five zero-day exploits coded inside, targeting vulnerable code in Windows," he said. "The complexity was, perhaps, because it was written to infect a target that was not connected to the Internet."

He, and Tiberious Axinte, technical lead at Bitdefender's Antimalware Lab, had yet to find out how APT28 infected systems with this newly discovered Mac payload, he said.

Once a Mac was infected, it was impossible to know, because the system would not display any unusual symptoms, Botezatu said. But, he added, the aim appeared to be stealing confidential information from businesses, military organisations, aerospace companies, power and utility companies and government bodies.


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Sam Varghese

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A professional journalist with decades of experience, Sam for nine years used DOS and then Windows, which led him to start experimenting with GNU/Linux in 1998. Since then he has written widely about the use of both free and open source software, and the people behind the code. His personal blog is titled Irregular Expression.